用Java編寫的實現(xiàn)加減乘除的程序如下
10年積累的網(wǎng)站設(shè)計制作、網(wǎng)站設(shè)計經(jīng)驗，可以快速應(yīng)對客戶對網(wǎng)站的新想法和需求。提供各種問題對應(yīng)的解決方案。讓選擇我們的客戶得到更好、更有力的網(wǎng)絡(luò)服務(wù)。我雖然不認(rèn)識你，你也不認(rèn)識我。但先做網(wǎng)站設(shè)計后付款的網(wǎng)站建設(shè)流程，更有佛坪免費網(wǎng)站建設(shè)讓你可以放心的選擇與我們合作。
import?java.awt.BorderLayout;
import?java.awt.event.ActionEvent;
import?java.awt.event.ActionListener;
import?javax.swing.JButton;
import?javax.swing.JComboBox;
import?javax.swing.JFrame;
import?javax.swing.JLabel;
import?javax.swing.JOptionPane;
import?javax.swing.JPanel;
import?javax.swing.JTextField;
public?class?Calculator?extends?JFrame?implements?ActionListener{
JLabel?jl1=new?JLabel("第一個數(shù)");
JLabel?jl2=new?JLabel("運算符");
JLabel?jl3=new?JLabel("第二個數(shù)");
JLabel?jl4=new?JLabel("結(jié)果:");
JTextField?jtf1=new?JTextField(8);
JTextField?jtf2=new?JTextField(8);
JTextField?jtf3=new?JTextField(8);
String?a[]={"+","-","*","/"};
JComboBoxString?jcb=new?JComboBoxString(a);
JButton?jb1=new?JButton("計算");
JButton?jb2=new?JButton("退出");
JPanel?jp=new?JPanel();
Calculator(){
setTitle("計算器");
jb1.addActionListener(this);
jb2.addActionListener(this);
jp.setLayout(null);
jl1.setBounds(30,?30,?80,?20);
jl2.setBounds(110,?30,?80,?20);
jl3.setBounds(190,?30,?80,?20);
jtf1.setBounds(30,?60,?70,?20);
jcb.setBounds(110,?60,?70,20);
jtf2.setBounds(190,?60,?70,?20);
jl4.setBounds(80,?110,?40,?20);
jtf3.setBounds(110,?110,?100,?20);
jb1.setBounds(60,?160,?60,?25);
jb2.setBounds(170,?160,?60,?25);
jp.add(jl1);jp.add(jl2);jp.add(jl3);
jp.add(jtf1);jp.add(jcb);jp.add(jtf2);
jp.add(jl4);jp.add(jtf3);
jp.add(jb1);jp.add(jb2);
add(jp,BorderLayout.CENTER);
setSize(300,?300);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLocationRelativeTo(null);
setVisible(true);
}
public?static?void?main(String[]?args)?{
new?Calculator();
}
@Override
public?void?actionPerformed(ActionEvent?ae)?{
if(ae.getSource()==jb1){
String?c=((String)?jcb.getSelectedItem()).trim();
if(jtf1.getText().trim().equals("")){
JOptionPane.showMessageDialog(this,?"第一個數(shù)不能為空");
jtf1.requestFocus();
return;
}
if(jtf2.getText().trim().equals("")){
JOptionPane.showMessageDialog(this,?"第二個數(shù)不能為空");
jtf2.requestFocus();
return;
}
double?num1=Double.parseDouble(jtf1.getText().trim());
double?num2=Double.parseDouble(jtf2.getText().trim());
double?num3?=?0;
switch(c){
case?"+":num3=num1+num2;break;
case?"-":num3=num1-num2;break;
case?"*":num3=num1*num2;break;
case?"/":
if(num2==0){
JOptionPane.showMessageDialog(this,?"除數(shù)不能為0");
jtf2.requestFocus();
return;
}else{
num3=num1/num2;
break;
}
}
jtf3.setText(String.valueOf(num3));
}
if(ae.getSource()==jb2){
System.exit(0);
}
}
}
運行結(jié)果
使用BigDecimal并且一定要用String來夠造。
實現(xiàn)方法如下：
import java.math.BigDecimal;
/**
* 由于Java的簡單類型不能夠精確的對浮點數(shù)進(jìn)行運算，這個工具類提供精
* 確的浮點數(shù)運算，包括加減乘除和四舍五入。
*/
public class Arith{
//默認(rèn)除法運算精度
private static final int DEF_DIV_SCALE = 10;
//這個類不能實例化
private Arith(){
}
/**
* 提供精確的加法運算。
* @param v1 被加數(shù)
* @param v2 加數(shù)
* @return 兩個參數(shù)的和
*/
public static double add(double v1,double v2){
BigDecimal b1 = new BigDecimal(Double.toString(v1));
BigDecimal b2 = new BigDecimal(Double.toString(v2));
return b1.add(b2).doubleValue();
}
/**
* 提供精確的減法運算。
* @param v1 被減數(shù)
* @param v2 減數(shù)
* @return 兩個參數(shù)的差
*/
public static double sub(double v1,double v2){
BigDecimal b1 = new BigDecimal(Double.toString(v1));
BigDecimal b2 = new BigDecimal(Double.toString(v2));
return b1.subtract(b2).doubleValue();
}
/**
* 提供精確的乘法運算。
* @param v1 被乘數(shù)
* @param v2 乘數(shù)
* @return 兩個參數(shù)的積
*/
public static double mul(double v1,double v2){
BigDecimal b1 = new BigDecimal(Double.toString(v1));
BigDecimal b2 = new BigDecimal(Double.toString(v2));
return b1.multiply(b2).doubleValue();
}
/**
* 提供（相對）精確的除法運算，當(dāng)發(fā)生除不盡的情況時，精確到
* 小數(shù)點以后10位，以后的數(shù)字四舍五入。
* @param v1 被除數(shù)
* @param v2 除數(shù)
* @return 兩個參數(shù)的商
*/
public static double div(double v1,double v2){
return div(v1,v2,DEF_DIV_SCALE);
}
/**
* 提供（相對）精確的除法運算。當(dāng)發(fā)生除不盡的情況時，由scale參數(shù)指
* 定精度，以后的數(shù)字四舍五入。
* @param v1 被除數(shù)
* @param v2 除數(shù)
* @param scale 表示表示需要精確到小數(shù)點以后幾位。
* @return 兩個參數(shù)的商
*/
public static double div(double v1,double v2,int scale){
if(scale0){
throw new IllegalArgumentException(
"The scale must be a positive integer or zero");
}
BigDecimal b1 = new BigDecimal(Double.toString(v1));
BigDecimal b2 = new BigDecimal(Double.toString(v2));
return b1.divide(b2,scale,BigDecimal.ROUND_HALF_UP).doubleValue();
}
/**
* 提供精確的小數(shù)位四舍五入處理。
* @param v 需要四舍五入的數(shù)字
* @param scale 小數(shù)點后保留幾位
* @return 四舍五入后的結(jié)果
*/
public static double round(double v,int scale){
if(scale0){
throw new IllegalArgumentException(
"The scale must be a positive integer or zero");
}
BigDecimal b = new BigDecimal(Double.toString(v));
BigDecimal one = new BigDecimal("1");
return b.divide(one,scale,BigDecimal.ROUND_HALF_UP).doubleValue();
}
};
分享
本回答由電腦網(wǎng)絡(luò)分類達(dá)人 高德寶認(rèn)證
其他類似問題
2009-02-08加減乘除運算（Java)14
2010-06-22Java實現(xiàn)有界面的簡單的兩個整數(shù)之間的加減乘除運算
2009-09-21myeclipse中java的加減乘除運算1
2011-05-27用java編寫計算器，，，要求加減乘除等運算。。。1
2011-09-15java中的String型怎么實現(xiàn)數(shù)學(xué)的加減乘除運算？10
更多關(guān)于java簡單加減乘除的問題
為您推薦：
舉報| 2009-02-24 03:00
#為什么很多走失的孩子無法找回？#
提問者采納
import java.util.Scanner;
class MakeOperation
{
public static void main(String[] args){
Scanner input=new Scanner(System.in);
Count count=new Count();
System.out.print("請輸入你要運算的第一個數(shù)：");
count.one=input.next();
System.out.print("請輸入你要進(jìn)行運算的運算符：");
count.fu=input.next();
System.out.print("請輸入你要運算的第二個數(shù)：");
count.two=input.next();
if(count.fu.equals("+")){
count.outcome=Float.parseFloat(count.one)+Float.parseFloat(count.two)+"";
// 將字符串解析為數(shù)字，注意下如果輸入的不是數(shù)字程序會報錯，缺少健壯性代碼 }
System.out.println(count);
}
}
class Count{
String one;
String two;
String fu;
String outcome; // 結(jié)果
public String toString(){
return one+fu+two+"="+outcome;
}
}
下面的代碼修改了Count類里域的部分參數(shù)，增加了一個用于檢查輸入是否正確的類。
import java.util.Scanner;
class MakeOperation
{
public static void main(String[] args){
Scanner input=new Scanner(System.in);
Count count=new Count();
CheckOperation checkOpera=new CheckOperation();
System.out.print("請輸入你要運算的第一個數(shù)：");
count.one=checkOpera.checkNum(input);
System.out.print("請輸入你要進(jìn)行運算的運算符：");
String[] operators={"+","-","*","/"};
count.fu=checkOpera.checkOperator(input,operators);
System.out.print("請輸入你要運算的第二個數(shù)：");
count.two=checkOpera.checkNum(input);
if("+".equals(count.fu)){
count.outcome=count.one+count.two;
System.out.println(count);
}
}
}
class Count{
float one;
float two;
String fu;
float outcome; // 結(jié)果
public String toString(){
return one+fu+two+"="+outcome;
}
}
class CheckOperation{
/*驗證數(shù)字，輸錯了會提示用戶重新輸入*/
public float checkNum(Scanner input){
float num=0f;
try {
num=Float.parseFloat(input.next());
} catch (NumberFormatException e) {
System.out.print("請輸入正確的數(shù)字: ");
num=checkNum(input); //直至獲取到正確的值
}
return num;
}
/*驗證輸入的符號是否正確*/
public String checkOperator(Scanner input,String[] operators){
String opera=null;
boolean judge=true;
opera=input.next();
for(String operator:operators){
if(operator.equals(opera)) judge=false;
}
if(judge) {
System.out.print("請輸入正確的運算符: ");
opera=checkOperator(input,operators);
}
return opera;
}
}
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class Calculator extends JFrame implements ActionListener
{
private boolean dotExist, operated, equaled; // 幫助運算的布爾變量
private double storedNumber; // 目前的結(jié)果
private char lastOperator; // 表示上一運算符
private JTextField operation; // 結(jié)果欄
private JButton dot, plus, minus, multi, div, sqrt, equal, changePN, clear; // 運算符
private JButton[] numbers; // 數(shù)字
// 構(gòu)造者
public Calculator()
{
setTitle("Calculator");
// 初始化變量
dotExist = false; // 表示當(dāng)前的數(shù)是否有小數(shù)點
operated = false; // 表示任意運算符是否被按下
equaled = false; // 表示等號是否被按下
storedNumber = 0;
lastOperator = '?';
// 初始化窗口變量
operation = new JTextField("0");
operation.setEditable(false);
numbers = new JButton[10];
for (int i = 0; i 10; i++)
numbers[i] = new JButton("" + i);
dot = new JButton(".");
plus = new JButton("+");
minus = new JButton("-");
multi = new JButton("*");
div = new JButton("/");
sqrt = new JButton("√");
equal = new JButton("=");
changePN = new JButton("±");
clear = new JButton("AC");
// 將窗口物體放入窗口
GridBagLayout layout = new GridBagLayout();
getContentPane().setLayout(layout);
addComponent(layout, operation, 0, 0, 4, 1);
addComponent(layout, numbers[1], 1, 0, 1, 1);
addComponent(layout, numbers[2], 1, 1, 1, 1);
addComponent(layout, numbers[3], 1, 2, 1, 1);
addComponent(layout, numbers[4], 2, 0, 1, 1);
addComponent(layout, numbers[5], 2, 1, 1, 1);
addComponent(layout, numbers[6], 2, 2, 1, 1);
addComponent(layout, numbers[7], 3, 0, 1, 1);
addComponent(layout, numbers[8], 3, 1, 1, 1);
addComponent(layout, numbers[9], 3, 2, 1, 1);
addComponent(layout, dot, 4, 0, 1, 1);
addComponent(layout, numbers[0], 4, 1, 1, 1);
addComponent(layout, sqrt, 4, 2, 1, 1);
addComponent(layout, plus, 1, 3, 1, 1);
addComponent(layout, minus, 2, 3, 1, 1);
addComponent(layout, multi, 3, 3, 1, 1);
addComponent(layout, div, 4, 3, 1, 1);
addComponent(layout, equal, 5, 0, 2, 1);
addComponent(layout, changePN, 5, 2, 1, 1);
addComponent(layout, clear, 5, 3, 1, 1);
}
// 對按鈕進(jìn)行反應(yīng)的方法
public void actionPerformed(ActionEvent e)
{
JButton btn = (JButton)e.getSource();
if (btn == clear)
{
operation.setText("0");
dotExist = false;
storedNumber = 0;
lastOperator = '?';
}
else if (btn == equal)
{
operate('=');
equaled = true;
}
else if (btn == plus)
{
operate('+');
equaled = false;
}
else if (btn == minus)
{
operate('-');
equaled = false;
}
else if (btn == multi)
{
operate('*');
equaled = false;
}
else if (btn == div)
{
operate('/');
equaled = false;
}
else if (btn == changePN)
{
operate('p');
operate('=');
equaled = true;
}
else if (btn == sqrt)
{
operate('s');
operate('=');
equaled = true;
}
else
{
if (equaled)
storedNumber = 0;
for (int i = 0; i 10; i++)
if (btn == numbers[i])
{
if (operation.getText().equals("0"))
operation.setText("" + i);
else if(! operated)
operation.setText(operation.getText() + i);
else
{
operation.setText("" + i);
operated = false;
}
}
if (btn == dot ! dotExist)
{
operation.setText(operation.getText() + ".");
dotExist = true;
}
}
}
// 進(jìn)行運算的方法
private void operate(char operator)
{
double currentNumber = Double.valueOf(operation.getText()).doubleValue();
if (lastOperator == '?')
storedNumber = currentNumber;
else if (lastOperator == '+')
storedNumber += currentNumber;
else if (lastOperator == '-')
storedNumber -= currentNumber;
else if (lastOperator == '*')
storedNumber *= currentNumber;
else if (lastOperator == '/')
storedNumber /= currentNumber;
else if (lastOperator == 'p')
storedNumber *= -1;
else if (lastOperator == 's')
storedNumber = Math.sqrt(currentNumber);
else if (lastOperator == '=' equaled)
storedNumber = currentNumber;
operation.setText("" + storedNumber);
operated = true;
lastOperator = operator;
}
// 快捷使用GridBagLayout的方法
private void addComponent(GridBagLayout layout, Component component, int row, int col, int width, int height)
{
GridBagConstraints constraints = new GridBagConstraints();
constraints.fill = GridBagConstraints.BOTH;
constraints.insets = new Insets(10, 2, 10, 2);
constraints.weightx = 100;
constraints.weighty = 100;
constraints.gridx = col;
constraints.gridy = row;
constraints.gridwidth = width;
constraints.gridheight = height;
layout.setConstraints(component, constraints);
if (component instanceof JButton)
((JButton)component).addActionListener(this);
getContentPane().add(component);
}
// 主方法初始化并顯示窗口
public static void main(String[] args)
{
Calculator calc = new Calculator();
calc.setSize(290, 400);
calc.setVisible(true);
}
}
重慶分公司
重慶分公司
